一个关于VC++的问题

编译时通过了
生成EXE时出现了问题如下：
inking...
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/窗口.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.
这是什么问题向大家请教一下
本人是初学者
源文件如下：#include<windows.h>
LRESULT CALLBACK WndProc(HWND ,UINT,WPARAM,LPARAM);
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevlnst,LPSTR lpszCmdLine,int nCmdShow)
{
HWND hwnd;
MSG Msg;
WNDCLASS wndclass;
char lpszClassName[]="windows";
char lpszTitle[]="my windows";
wndclass.style=0;
wndclass.lpfnWndProc=WndProc;
wndclass.cbClsExtra=0;
wndclass.cbWndExtra=0;
wndclass.hInstance=hInstance;
wndclass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);
wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName=NULL;
wndclass.lpszClassName=lpszClassName;
if(!RegisterClass(&wndclass))
{
MessageBeep(0);
return FALSE;
}
hwnd=CreateWindow(
lpszClassName,
lpszTitle,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL,
);
ShowWindow(hwnd,nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&Msg,NULL,0,0))
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
PostQuitMessage(0);
default:
return DefWindowProc(hwnd,message,wParam,lParam);
}
return(0);
}